Rehabilitation therapy following any injury is very important. This is so both in terms of the time required for rehabilitation and the effectiveness of the rehabilitation. Fortunately, it is known that proper exercise of the affected anatomy shortens the time for recovery and improves the effectiveness of the rehabilitation. In specific cases where there has been injury to the ankle, knee or hip, it has been suggested that post operative rehabilitation follow a sequence of activities which includes crutch walking, cycling and running. Each of these activities, however, must be carefully monitored and controlled in order to optimize the effect of the exercise.
When exercise cycles are used in rehabilitation therapy, there are some limitations which need to be appreciated. Namely, with any exercise cycle, the feet are confined, or perhaps even forced, to move along definable paths. Consequently, the leg (which for purposes of the discussion here, includes the hip, the knee and the ankle) will assume different angulations depending on the position of the hip relative to the paths of the feet. To the extent the leg is thereby forced into painful positions, a cycling exercise may be counterproductive.
In order to better appreciate leg geometry during a cycling exercise, it is helpful to understand the notions of extension and flexion. Specifically, extension is the movement of the leg which brings its members, i.e. femur and tibia, into or toward a straight condition. Accordingly, the maximum angle of extension for the leg is the angle between the attainable extension and this straight condition. On the other leg, whereas extension pertains to the straightening of the leg, flexion pertains to the bending of the leg away from the straight condition. Accordingly, the maximum angle of flexion is the angle between the attainable flexion and the straight condition. With any given injury to the knee, the maximum angle of extension, or the maximum angle of flexion, or both, may be limited from what would ordinarily be considered normal. Typically, for normal conditions, the angle at maximum extension is zero degrees (0.degree.) and at maximum flexion is approximately one hundred twenty degrees (120.degree.). Unfortunately, restrictions on this range of movement can result from any one of several conditions.
For example, in order to facilitate recovery following reconstructive surgery of the anterior cruciate ligament (ACL) in the knee joint, the ACL should not be stressed or loaded during the rehabilitation period. Consequently, extension is limited. Specifically, in order to avoid loading the ACL, it is known the leg should not be extended to a point where the extension angle is less than approximately forty-five degrees (45.degree.). As another example, in conditions where there is anterior patellar pain, i.e. the knee cap hurts, it is commonly observed that the angle of flexion cannot exceed approximately ninety degrees (90.degree.) without causing excessive pain. In addition to these specific examples, leg movement may be impaired in numerous ways by injury or by complications following corrective surgery. Furthermore, all knee difficulties, regardless of their nature, can only be aggravated by concurrent ankle or hip impairments.
In any event, the objectives of lower body rehabilitation following injuries include providing cardiovascular exercise, preventing quadriceps atrophy, aiding in maintenance or recovery of thigh girth, and realizing an early return for the patient to the activities of daily living. The present invention recognizes that the ankle, knee and hip can be injured at the same time and must therefore be treated simultaneously in an exercise program. Thus, the present invention also recognizes that in order to properly exercise the leg during rehabilitation therapy, an exercise cycle is needed which can concurrently accommodate limitation to knee or hip motion.
In light of the above, it is an object of the present invention to provide an exercise cycle which has multiple adjustment points to accommodate limited ranges of motion of the hip or knee. Another object of the present invention is to provide an exercise cycle which is able to provide a patient with proper cardiovascular exercise while sparing the patient from painful movements of the knee or hip. Still another object of the present invention is to provide an exercise cycle which can concurrently accommodate limited ranges of motion for both legs. Yet another object of the present invention is to provide an exercise cycle which is simple to operate, relatively easy to manufacture and comparatively cost effective.